Field of the Invention
The invention relates to a vibration reducing technique for a reciprocating power tool, such as a reciprocating saw and a jig saw, which performs a cutting operation on a workpiece by reciprocating a tool bit.
Description of the Related Art
Japanese non-examined laid-open Patent Publication No. 2005-14111 discloses a reciprocating saw in which, when a slider with a tool bit reciprocates via a crank by a motor in order to perform a cutting operation by the tool bit, a counter weight reciprocates to opposite to a slider. Specifically, the counter weight is caused to linearly move in a direction opposite to the slider, so that vibration caused by reciprocating motion of the slider is reduced.
According to the vibration reducing method for the reciprocating saw in which the counter weight reciprocates in a phase opposite to linear reciprocating motion of the slider, the momenta of the slider and the counter weight which mainly includes inertial force can cancel each other out in the longitudinal direction of the slider, so that vibration reduction can be rationally realized. However, vibration is caused by collision when the counter weight reverses its direction of movement, and energy loss is caused by the reversal of direction. In this respect, further improvement is desired.